An Improved CoAP Scheme for 6LoWPAN Networks
Heng Wang, Na Bao, Ping Wang · Advances in intelligent systems research/Advances in Intelligent Systems Research · 2014
CoAP (Constrained Application Protocol) is a lightweight protocol proposed and standardized by IETF (Internet Engineering Task Force).It is designed for constrained environments, such as sensor nodes and sensor networks.In this paper, we present an improved CoAP scheme based on 6LoWPAN (IPv6 over Low power Wireless Personal Area Network) networks.The existing CoAP proxy mechanism requires a large cache space in proxy endpoints and is not optimized for large sensor networks.An enhanced proxy and cache mechanism of CoAP is designed to address this issue.The proposed mechanism uses query mode of discovery and significantly reduces the energy consumption and cache space usage.The cache is a two-dimensional array that stores resource information and identifiers with same structure at each line.Moreover, considering the alarm service widely used in the sensor networks, we also add a simple alarm method in CoAP to support the transmission of alarm information.The improved proxy and alarm mechanisms are implemented and verified in a 6LoWPAN platform.